一种多波长信号全光加密系统方案

为了能够同时对多波长信号进行加密操作,两路相干光信号进行直接干涉前,通过对其中一路光信号进行Pi相移,Pi相移后两路信号的干涉结果即为两信号异或(XOR)逻辑结果。基于此原理,提出一种应用于波分复用(WDM)系统,能够同时对多波长复用信号进行XOR加密的方案。方案通过直接电光调制得到不同波长相干光信号与光密钥,且通过相移单元同时对多波长光密钥进行Pi相移,相移后相同波长的光密钥与光信号的耦合干涉输出便是对光信号的XOR加密结果,并输出多波长复用的加密信号。通过8×10Gbit/ps的WDM信号的加密仿真得到该方案加密输出误码率(EBR)为0,Q因子为164,证实了方案的可行性与有效性。分析了脉冲占空比对加密输出信号Q因子的影响。通过理论与仿真分析了输入归零码信号占空比对加密信号质量的影响得出,当信号占空比小于0.43时,加密输出信号Q因子能够稳定在164左右。

An all-optical multi-wavelength encryption system

In order to encrypt multi-wave input signals simultaneously,according to the analysis of the effect of light interference,we conclude that XOR encrypting operation can be realized by the interference of two coherent optical signals on e of which is given pi phase shift before they combining.According to this concl usion,an all-optical encryption system which can be used in wavelength division multiple xing (WDM) system and encrypting multi-wavelength optical signals is proposed.This scheme achieves multi-wave l ength coherent optical signals and optical keys by direct electro-optics modulation ,and achieves pi phase shift of multi-wavelength optical keys by phase shifter,then the XOR encrypting operation for optical signals can be realized by the combining and interferring of optical signal and key which have the same wavelength,and then t he multi-wavelength encrypted result is output.The feasibility and effectivenes s of this system are confirmed by the simulation of encrypting operation of 8×10Gbit/ps WDM signal s.The bit error rate (BER) and Q factor of encrypting output are 0and 164,resp ectively.Moreover,this paper analyzes the Q factors of e ncryption output at different duty cycles of input signals.When the duty cycle o f input signal is smaller than 0.43,the Q factor of encr ypted result is about 164.